Gripper mechanism for printing-presses.



Patented July I, I902. R. Ml-EHLE.

'GRIPPEB MECHANISM FOR PRINTING PRBSSES.

(Application filed June 15, 1901.)

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UNITED STATES,

PATENr Orrrcn.

ROBERT MIEIILE, OF CHICAGO, ILLINOIS.

GRIP'PER MECHANISM For: PRINTING- PRESSES.

SPECIFICATION forming part of Letters Patent No. 703,605, dated July 1, 1902.

I Application filed June 15,1901 Serial No. 64,631. (No model.)

To all whom it may concern:

Be it known that 1, RO ERT MIEHLE, a citizen of the United States, residing at Chicago, in the county of Cook and. State of Illinois, have invented a new and useful Improvement in Gripper Mechanism for Printing Presses, of which the following is a specifica-. tion.

This invention is an improvement in gripper mechanism for sheet-printing presses such, for example, as shown in my Patent No. 574,207, of December 29, 1S96and has par ticular reference to the construction of the tumbler or cross-head on the cylinder-gripper shaft, as hereinafter fully explained.

The object of the invention is to prevent rebounding of the gripper-fingers when they close upon a sheet of paper, thereby enabling the press to be operated accurately at a much higher speed than is possible with the usual construction of gripper mechanism. When sheet-printing presses are operated at low speeds, the ordinary gripper mechanisms actefficiently, but when operated at high speeds great trouble has been experienced in.obtaining accurate register of impressions and accurate presentation of the sheets to the type-forms from. the fact that the gripperfingers rebound. The grippers, as is well known, are closed by. springs arranged to rock the gripper-shaft, the rocking of the shaft being accomplished by means of a tumbler on the end thereof engaging a tumbler-pin on the frame, so that as the tumbler moves past the pin the latter enters a slot in the tumbler and'causes the latter to turn and rock the gripper-shaft, so as to throw the grippers past the dead-center,

whereupon the spring comes into action and quickly completes the throw of the shaft,

holding the grippers open or closed, as the case may be, until the tumbler is actuated in the opposite direction. The spring causes the gripper-fingers in closing to violently snap down on the bar, and naturally there is a rebound, which for an instant leaves the sheet of paper free before the? grippers finally settle down. The rebounding interval is of course very short, and at low speeds no great difficulty results; but at high speeds the peripheral movement of the cylinder is so great that the edge of the sheet will slip perceptibly in grippers, as usual.

this minute interval, and it therefore results that the register is destroyed at high speeds. Thisrdefect the present invention overcomes by preventing the rebound, which is accomplished by the means and-in the manner-hereinafter described and claimed, and the accompanying drawings illustrate a construction embodying the invention, which I will now describe.

In the accompanying drawings, Figure 1 is an end view of the cylinder of a printingpress, showing the grippers just closed upon a sheet. Fig. 2 is a detail side elevation of the parts shown in Fig. 1. Fig. 3 is a view similar to Fig. 1, showing the grippers open. Fig. 4 is an enlarged elevationot the crosshead. Figs. 5, 6, 7, 8, 9, and 10 are:diagrammatic views, illustrating the different positions assumed by the tumbler relative to the stationarypin in closing the'igrippers, Figs. 8 and 9 showing the dwell or retardation of closing of-the fingers just priortoi-nipping the sheet. 7V

In said drawings, 5 represents an" impression-cylinder, to which the gripper mechanism is applied.

6 is the feed-table, from which the sheets are fed to the cylinder, and 7 is the shaft of the cylinder. A series of gripper-fingers S are mounted on a rock-shaft 9, extending 1ongitudinally of .the cylinder. This shaft is rocked at proper times, either to cause the 'it to turnthe rock-shaft 9 alternately in 0pposite directions, so as to ope n-or close the The pins 13 and l t are located one in the orbital path traversed by the mouth of tumbler-slotll'and the other in the orbital path traversed by the mouth of tumbler-slot 12, so that they can properly enter their respective slots. In some cases, as in a two-revolution press, the pins are made to slide into and away from the-path of the tumbler, so they may be made-to engage the latter only during certain revolutions of the cylinder and be idle during other revolutions thereof. Again, in other presses the pins are stationary and engage the tumbler at each revolution of the cylinder. The usual spring 15 and rod 16, joined to arm 17 on the nipper-shaft, are employed to throw the shaft 9 and hold the grippers closed or open until the shaft is again rocked by the engagement of the tumbler and a pin. A stop 18 limits the movements of the cross-head.

In opening the grippers the pin 14 engages the slot 12 and causes the tumbler to rock shaft 9 to the right, opening the grippers, until the arm 16 passes the dead-center, whereupon spring 15 comes into play and throws the grippers quickly fully open and holds them so until tumbler 10 engages pin 13. The grippers are closed in like manner by pin 13 engaging slot 11 of the tumbler.

In order to prevent rebound of the grippers in closing, I make the slot 11 of peculiar form on its right-hand side and long enough to retain control of the grippers until they have finally closed upon the sheet instead of permitting the spring 15 to slam the grippers down upon the sheet (and rebound) as soon as the tumbler and pin 13 have rocked arm 17 past the dead-center. For this purpose the right-hand or finally-closed side of slot 11 is formed with a concavity 19, which permits the spring to almost close the gripper with great rapidity, but arrests the grippers and retards or causes them to dwell momentarily before they actually nip the sheet. This action is clearly illustrated in Figs. 5 to 10. Fig. 5 shows pin 13 just entering the slot 11 and engaging the left-hand side thereof. As the cylinder moves, carrying shaft 9 past pin 13, the tumbler is caused to rock, slot 11 slipping upon pin 13, which continues to press against the left-hand side of slot 11 until it reaches the position shown in Fig. 7. Then the pin 13 impinges against the right-hand side of slot 11, (while the tumbler begins to slip off the pin.) Spring 15 having come into play holds the tumbler against the pin, and when the pin reaches the center of concavity 19, as shown in Fig. 8, the grippers are almost the grippers close easily against the edge of the cylinder (or bar therein) upon which the leading edge of the sheet is held by the grippers. The left side of the slot 11 has an outward curve 21 opposite curve 19; but this is not an essential feature.

The improved tumbler allows the grippers to close rapidly; but just before they nip the sheetthey are retarded or caused to dwell sufliciently to destroy their momentum, and then they finally nip the sheet without any rebound. The invention, while apparently slight, has obviated a difliculty long experienced and for which many remedies have been sought and has practically enabled the speed of the presses to be greatlyincreased and has produced improved results both in the quantity of work and quality of registration.

Having thus described myinvention, what I therefore claim as new, and desire to secure by Letters Patent thereon, is-

1. The herein-described tumbler for gripper mechanisms, having a pin-engaging slot, provided with a concavity in its side adapted to cause the grippers to dwell momentarily in closing just prior to nipping the sheet, substantially as and for the purpose described.

2. In a gripper mechanism for printingpresses, the combination of the cylinder, gripper-shaft and tumbler-engaging pin, with a tumbler on the gripper-shaft having a slot adapted to engage the pin in closing the grippers, and said slot having its side so shaped or concaved at the point traversed by the pin in closing that the motion of the grippers is arrested or retarded just prior to nipping the sheet and the grippers closed thereon without rebound, substantially as described.

ROBERT MIEIILE.

Witnesses:

Enw. S. EVARTS, H. M. MUNDAY. 

